The Kynix Blog

Warm hints: The word in this article is about 2500 and  reading time is about 12 minutes. The fiber optic sensor consists of the light source, incident fiber, exit fiber, light modulator, light detector, and demodulator. The basic principle is that the light of the light source is sent to the modulation area through the incident optical fiber, and the light interacts with the measured parameters in the modulation area to change the optical property of the light into the modulated signal light which is then sent through the outgoing fiber optical detector, demodulator and get the measured parameters. In recent years, sensors have evolved in the direction of sensitivity, precision, adaptability, compactness, and intelligence.  Optical fiber has many excellent properties, such as anti-electromagnetic interference and atomic radiation performance, soft and lightweight mechanical properties. Insulation, non-responsive electrical properties. Water, heat, and corrosion resistance of chemical properties, can reach people's eyes and ears in unattainable places (such as high-temperature areas), or in areas harmful to humans (such as nuclear radiation area), but also can transcend human physiological boundaries and receive sensory organs Unexpected outside information.   Catalogs I. Basic Structure and Principle of Fiber Optic SensorII. Application of Light Sensor in Petrochemical Industry2.1 The application of fiber optic sensor in the   petrochemical system2.2 The application of fiber optic sensor in oil   loggingIII. Application of Fiber Optic Sensors in Power Systems3.1 Applications in the high voltage cable temperature   and strain measurement3.2 Application in Electric Power Sensors3.3 Application of optical fiber cable monitoringIV. Fiber Optic Sensors in Medical Applications4.1 Pressure measurement4.2 Blood flow velocity measurement4.3 PH measurementV. Fiber Optic Sensor FeaturesFAQ  I. Basic Structure and Principle of Fiber Optic Sensor The fiber optic sensor consists of the light source, incident fiber, exit fiber, light modulator, light detector, and demodulator. The basic principle is that the light of the light source is sent to the modulation area via the incident fiber, and the light interacts with the measured parameters in the modulation area to make the optical properties (such as intensity, wavelength, frequency, phase, and normality) of the light occur Changes into a modulated signal light, and then sent through the optical fiber into the optical detector, demodulator to obtain the measured parameters. Fiber optic sensors can be divided into two categories by sensing principle: one is the light transmission (non-functional type) sensor, the other is the sensor type (functional) sensor. In the fiber optic sensor, the optical fiber only as a light transmission medium, the measured signal is detected by other sensitive components, this exit fiber, and the incident optical fiber is not continuous. Between the two Modulators are spectrally sensitive or other types of sensitive elements. In the sensing type fiber optic sensor, the optical fiber has both the sensitivity to the signal to be measured and the transmission of the optical signal. And the "sense" and "pass" of the signal are combined so that the optical fiber in such a sensor is continuous. Due to the different roles played by the optical fibers in these two sensors, the requirements for the optical fibers are also different. Optical fiber in the light-transmitting sensor only plays the role of light transmission. The use of communication fiber even ordinary multi-mode fiber can meet the requirements, and sensitive components can be a very flexible selection of high-quality materials. So the sensitivity of these sensors needs more optical coupling devices, the structure is more complex. The structure of sensing type fiber optic sensor is relatively simple with fewer coupling devices, but higher requirements on the optical fiber. It often needs to be sensitive to signal measurement, with good transmission characteristics. So far, most people adopt the former, but with the improvement of optical fiber manufacturing technology, sensor-type fiber optic sensors will also be widely used. According to the principle of light being modulated in optical fiber, fiber optic sensors can be divided into intensity modulation, phase modulation, polarization modulation, frequency modulation, wavelength modulation, and so on. Up to now, optical sensors have been able to measure more than 70 physical quantities. Fiber Optic Sensors have unique advantages over traditional sensors. (1) High sensitivity. Since light is a very short wavelength electromagnetic wave, its optical length is obtained by the phase of light. Taking an optical fiber interferometer as an example, due to the small diameter of the fiber used, its optical length is subject to slight mechanical external force or temperature change, causing a large phase change. Suppose that with a 10-meter optical fiber, a change of 1 ° C causes a phase change of 1000ard. If the minimum phase change that can be detected is 0.01ard, the minimum change in temperature that can be measured is 10 ° C, showing a high sensitivity. (2) Anti-electromagnetic interference, electrical insulation, corrosion resistance, intrinsically safe. Since fiber optic sensors transmit information using light waves, optical fibers are an electrically insulating, corrosion-resistant transmission medium and safe, which makes it easy and effective to use All kinds of large electromechanical, petrochemical, mine and other strong electromagnetic interference and flammable and explosive and other harsh environments. (3) Fast measurement. Light travels fastest and can transmit two-dimensional information, so it can be used for high-speed measurements. The analysis of radar and other signals requires an extremely high detection rate. The application of electronics is difficult to achieve. Using high-speed spectral analysis of light diffraction can be solved. (4) Large information capacity. The signal under test is a light wave carrier, and the light has a very high frequency. The contained frequency band is very wide. The same optical fiber can transmit multiple signals. (5) Suitable for harsh environments. Optical fiber is a dielectric, high voltage, corrosion-resistant, anti-electromagnetic interference that can be used for other sensors that do not adapt to the harsh environment. In addition, fiber-optic sensors are also characterized by their lightweight, small size, flexibility, wide measurement range, good reusability, and low cost. The application of fiber optic sensors is precise because fiber optic sensors have so many advantages, making it a very wide range of applications, involving petrochemicals, power, medicine, civil engineering, and many other fields. Video 1 Introduction of fiber optic sensorsII. Application of Light Sensor in Petrochemical Industry 2.1 The application of fiber optic sensor in the petrochemical systemIn the petrochemical system, due to the underground environment with high temperature, high pressure, chemical corrosion and electromagnetic interference, and other characteristics, the conventional sensor is difficult to play a role in the well. However, the fiber itself is no charge, small and light, easy to bend, anti-electromagnetic interference, and anti-radiation performance. Particularly it is suitable for flammable and explosive, strict restrictions and strong electromagnetic interference, and other harsh environments. Fiber optic sensors in the measurement of the good parameters play an irreplaceable role. It will become the oil and gas exploration and oil logging and other logging A field of broad market prospects of new technologies.  Fiber optic sensor application in oil and gas exploration. Because of its high-temperature capability, multi-communications, distributed sensing capabilities, and the fact that it requires only a small space to meet its use conditions, fiber optic sensors make it particularly unique in exploration drilling. The application of fiber optic sensors can be made into the downhole spectrometer, distributed temperature sensor, and optical fiber pressure sensor, and other products suitable for this special job requirement. (1) The downhole spectrometer fluid analyzer shown in Figure 1 can be used to understand the crude oil composition during the initial development process. It consists of two sensors: one is the absorption spectroscopy fiber and the other is the fluorescence and gas detector. Downhole fluid is introduced into the tubing by formation probes and the optical sensor is used to analyze the fluid within the tubing. Fluid analysis spectrometers provide in-situ downhole fluid analysis and improve formation fluid evaluation. (2) Distributed temperature sensors. Optical fiber distributed temperature sensors are the most popular fiber optic sensors for downhole applications. The application example is to monitor the steam injection heavy oil recovery system. Steam is injected into the heavy oil reservoir to reduce the viscosity of the oil, allowing heavy oil to be mined out. Downhole steam temperature can be as high as 250 ℃. Figure 1 Fluid analyzer structure(3) The fiber-optic pressure sensor is currently under development. Its main focus is on ultra-high temperature and downhole pressure monitoring tasks. Other commercial products based on fiber optic sensors are currently available. For example, fiber optic probes for multiphase flow measurements and distributed dynamic strain measurements. Its high reliability, high efficiency, and low power consumption are key factors in the success of optical fiber products in oil field applications. 2.2 The application of fiber optic sensor in oil loggingOil logging is one of the most basic and key aspects of the petroleum industry. The parameters such as pressure, temperature, and flow rate are important physical quantities in oil and gas wells. These advanced technologies are used for long-term Real-time monitoring, timely access to the information of oil and gas wells, the oil industry has a very important significance. Fiber optic sensors are insensitive to electromagnetic interference and withstand extreme conditions, including high temperatures and pressures, as well as strong shock and vibration, to measure borehole and well site environmental parameters with high accuracy, and have distributed measurement capabilities for fiber optic sensors. The spatial distribution gives the profile information. Moreover, the fiber optic sensor cross-sectional area is small, short in shape, in the wellbore occupies a very small space. Traditional electronic sensors do not have such features in the harsh underground environment. Fiber optic sensors can do downhole flow measurement, temperature measurement, pressure measurement, water (gas) measurement, density measurement, acoustic measurement. (1) Flow measurement. Because the intensity, phase, frequency, wavelength, and other characteristics of light in the optical fiber transmission process will be subject to flow modulation. A certain light detection method can convert the modulation into electrical signals, you can find the fluid flow, which is the fiber flow the working principle of the meter. (2) Temperature and pressure measurement. The distributed optical fiber measurement system (DTS) utilizes the Raman effect of the optical fiber to enable real-time monitoring of the temperature field where the fiber is located. The EFPI type (non-intrinsic FP interference) and FBG fiber optic sensors are wavelength-coded sensors. With high sensitivity, it also can simultaneously measure pressure, temperature, stress, and other parameters of the characteristics. The optical fiber thermal color temperature sensor is a reflective temperature sensor composed of a white light source and a multi-mode optical fiber.  The optical fiber radiation temperature sensor utilizes black body radiation energy. Its non-contact, measurable instantaneous temperature, fast response, and no need for heat balance time are available. In high-temperature measurement, the semiconductor absorption-type optical fiber temperature sensor utilizes the characteristic that the absorption edge wavelength of its semiconductor material shifts to a longer wavelength as the temperature increases, and an appropriate semiconductor light-emitting diode is selected so that its spectral range falls exactly on the absorption edge region. , So the light intensity through the semiconductor decreases with increasing temperature. (3)Water (Gas) Rate and transmission power of U-shaped fiber used for density measurement vary with the refractive index of the external medium. The lightwave serves as an information carrier and has nothing to do with the resistivity, flow pattern, and water quality of the mixed fluid. The fiber holding rate is based on this principle. The density sensor essentially solves the problem of the application of high water content without resolution and radioactive substances in the existing holding ratios. For the multi-phase fluids, the refractive indices of oil, water, and gas are all different, so the refractive index of the mixed fluid will follow. Change the ratio of oil, water, gas changes. Therefore, this refractive index modulation type fiber optic sensor can not only measure the fluid holding rate, fluid density can be measured at the same time, for its accuracy is higher. (4) Sonic measurement. Seismic waves propagate in different media and the waveforms of the received seismic waves will be different. According to different seismic waveforms, the sedimentary sequence and sedimentary structure can be identified to locate the reservoir, determine the gutter, detect the damage and fracture of the casing, and perforation, detect layers and determine the fluid flow, and so on. VSP seismic logging means that the geophone is placed in a well and the seismic signal is received by the geophone in the well by means of a micro-vibration generated by ground-derived seismic waves or fluid flow in the well.  The permanent downhole optical fiber three-component seismic survey has high sensitivity and directionality can produce high-precision spatial images. It can not only provide near-borehole images but also can provide strata images around the wellbore. And the measurement range can reach thousands of kilometers. It withstands harsh environmental conditions and has no moving parts and downhole electronics that can withstand strong shocks and vibrations and Can be installed in an extremely small space for complex completion string.  III. Application of Fiber Optic Sensors in Power Systems Because of the complicated structure and wide distribution of power system networks, various hidden dangers exist on the high-voltage power line and power communication network. Therefore, it is very important for distributed monitoring of various lines and networks in the system.  3.1 Applications in the high voltage cable temperature and strain measurementAt present, foreign countries (mainly Britain, Japan, etc.) have developed the distributed optical fiber temperature sensor products by utilizing the laser Raman spectroscopy effect. And domestically, we are actively carrying out research work in this area. The domestic begin to introduce the distributed optical fiber temperature sensing technology into the power system cable temperature measurement. In connection with the snow disasters suffered in southern China last year, we can consider that if we can lay sensor fiber optic cables in parallel on high-voltage cables and measure the temperature, pressure, and other parameters of power system cables and towers in real-time, we can make timely measurements, so as to minimize economic losses.  Fiber optic sensors in the power system will have a wide range of applications. Ideally, the fiber should be placed as close as possible to the cable core to more accurately measure the actual cable temperature. For direct-buried power cables, although the surface-mount fiber can not accurately reflect the change of cable load, it is more sensitive to the change of thermal resistivity of soil in the buried cable and can reduce the installation cost of optical fiber. 3.2 Application in electric power sensorsElectric power is the basic power reflecting the energy conversion and transmission in the power system. Electric power measurement is an important part of power metering. With the rapid development of the power industry, traditional electromagnetic measurement methods have increasingly exposed their inherent limitations, such as electrical insulation, electromagnetic interference, and magnetic saturation.  Therefore, people have been working hard to find new methods for measuring electrical power. It can be said that the advent of fiber optic sensors has brought people the gospel to solve this problem. The main characteristics of fiber-optic power sensors are: Since electric power sensing involves both voltage and current at the same time, it is usually necessary to consider both electro-optic and magneto-optic effects. At the same time, two kinds of sensing media or one multifunctional media are used as sensitive elements. The structure of the fiber electric power sensor head is relatively complicated; the optical sensor signal of the fiber electric power sensor sometimes includes voltage and current signals at the same time, so the signal detection and processing methods thereof will also be more complicated. 3.3  Application of optical fiber cable monitoringIn Power Systems The power system has a wide variety of optical cables. In addition, China has a vast area and the environment varies widely. Therefore, the environment of optical cables is also very complex. Temperature and stress are the main environmental factors that affect the performance of optical cables. Therefore, while monitoring the breakpoint of the optical fiber, the temperature and stress conditions of the optical cable are also monitored. It can be seen that the optical fiber cable has far-reaching fault warning and maintenance.  By measuring the frequency shift and intensity of the Brillouin scattered light along the length of the optical fiber, the temperature and strain information of the optical fiber can be obtained, and the sensing distance is relatively long, so it has far-reaching engineering research value. Based on Brillouin Optical Time Domain Reflectance (BOTDR) distributed optical fiber sensing system, using coherent detection technology, the system principle shown in Figure 2.  Figure 2 based on BOTDR sensing system principleThe BOTDR fiber sensing system measures the self-distribution of scattering signals of an optical fiber and its signal strength is very weak, but the coherent detection technology can be used to improve the signal-noise ratio of the system. This solution can be a single light source, single-ended work, the system is simple and easy to implement, and can simultaneously detect fiber breakpoints, loss, temperature, and strain.  IV. Fiber Optic Sensors in Medical Applications In medical fiber, sensors are mainly light-transmitting. With its small size, insulation, non-radio frequency, and microwave interference, high measurement accuracy and good affinity with living organisms, and other advantages. This article will mainly introduce the application of transmission optical fiber in pressure measurement, blood flow velocity measurement, and pH measurement. In addition, it can also be applied to the measurement of temperature and medical image transmission. 4.1 Pressure measurementCurrent clinically applied pressure sensors are mainly used to measure intravascular blood pressure, intracranial pressure, intracardiac pressure, bladder, and urethral pressure. The pressure sensor used to measure blood pressure is schematically shown in Figure3. The pressure-sensitive part is a water-repellent film on the sidewall of the tip of the probe catheter connected to the membrane by a cantilever micromirror and an optical fiber opposite the reflector for transmitting incident light to the reflector while The reflected light is also transmitted.  When there is pressure on the film, the film is deformed and can drive the cantilever to change the angle of the mirror. The light beam coming from the fiber is shone on the mirror and then reflected at the end of the fiber. Since the direction of the reflected light changes with the angle of the mirror, the intensity of the reflected light received by the optical fiber also varies. This change passes through the optical fiber to the other end of the photodetector into an electrical signal, so that by changing the voltage to know the size of the probe at the pressure.Figure 3 Optical fiber pressure gauge probe 4.2 Blood flow velocity measurement Doppler-type optical fiber speed sensor measurement of subcutaneous tissue flow velocity shown in Figure 4, this device uses the optical fiber end reflection phenomenon, the measurement system is simple in structure.Figure 4 optical fiber pressure gauge probeLaser light with a frequency of f passes through the lens and the fiber is sent to the epidermal tissue. For immobile tissue, such as the vessel wall, the reflected light does not produce a frequency shift; and for the red blood cells in the cortex capillary flow rate, the reflected light to produce a frequency shift, the frequency change △ f. The frequency shift of the reflected light The intensity is proportional to the concentration of erythrocytes and the change in frequency can be proportional to the velocity of erythrocytes. Emitted light collected by the optical fiber, the first on the light detector for mixing, and then into the signal processing instrument, which get the red blood cell velocity and concentration. 4.3 PH measurementA schematic diagram of the pH fiber optic sensor used to determine tissue and blood values is shown in Figure 4. Its working principle is the use of emission light, the intensity of transmitted light with the wavelength distribution of the spectrum to be measured. The sensor inserts two optical fibers into an ion-permeable cellulose capsule containing reagent, which penetrates the reagent when the needle is inserted into the tissue or blood vessel, causing the reagent to absorb light of a certain wavelength. Measured such changes, you can get the blood or tissue pH.Figure 5 Determination of pH fiber spectrometerV. Fiber Optic Sensor Features 1.High sensitivity. 2.The geometry has a wide range of adaptability, can be made into any shape of the fiber optic sensor. 3.You can create sensors sensing a variety of different physical information (sound, magnetic, temperature, rotation, etc.) of the device. 4.Can be used for high voltage, electrical noise, high temperature, corrosion, or other harsh environments. 5.But also with the inherent compatibility of optical telemetry technology. The advantages of fiber-optic sensors are that optical fiber sensors use light as a carrier for sensitive information, and use optical fibers as a medium for transmitting sensitive information. Compared with conventional sensors. They have the characteristics of optical fiber and optical measurement and have a series of unique advantages. Good electrical insulation, anti-electromagnetic interference, non-invasive, high sensitivity, easy to achieve long-distance monitoring of the signal under test, corrosion resistance, explosion-proof, flexible optical path, easy to connect with the computer. Sensors are developed in the direction of sensitivity, precision, adaptability, compactness, and intelligence. They can serve as human eyes and ears where people cannot reach(such as high-temperature areas, are as harmful to humans, or nuclear radiation areas). But it is also beyond the physical boundaries of human beings, outsiders can not feel the sensory information. FAQ 1. How does a fiber optic sensor work?Fiber optic sensors work based on the principle that light from a laser or any superluminescent source is transmitted via an optical fiber, experiences changes in its parameters either in the optical fiber or fiber Bragg gratings and reaches a detector which measures these changes. 2. What are fiber optic sensors used for?Optical fibers can be used as sensors to measure strain, temperature, pressure and other quantities by modifying a fiber so that the quantity to be measured modulates the intensity, phase, polarization, wavelength or transit time of light in the fiber. 3.How are fiber optic sensors classified?Based on the operating principle or modulation and demodulation process, a optical fiber sensor can be classified as intensity, a phase, a frequency, or a polarization sensor. All these parameters may be subject to change due to external perturbations. ... These sensors are widely used as chemical sensors. 4. What is active and passive optical fiber sensor?Active fibre optic. -In optical fiber communication, because the signal usually decades during long distance transformation, you need to add an amplifier to boost the signal. Passive fibre optic. - Simply receive light data from the environment, it is commonly used for illumination (Fiber optical lighting. 5. What are the characteristics of optical fiber sensors?Optical fiber sensors have unique advantages, such as high sensitivity, immunity to electromagnetic interference, small size, light weight, robustness, flexibility, and the ability to provide multiplexed or distributed sensing. 6. Which is a use of fiber optics?They are widely used in lighting, both in the interior and exterior of vehicles. Because of its ability to conserve space and provide superior lighting, fiber optics is used in more vehicles every day. Also, fiber optic cables can transmit signals between different parts of the vehicle at very fast speed. 7. Why optical fiber is used for communication?Optical fiber is used by telecommunications companies to transmit telephone signals, Internet communication and cable television signals. ... Due to lower attenuation and interference, optical fiber has advantages over copper wire in long-distance, high-bandwidth applications. 8. Is fiber optic WIFI?Like any Internet service, fiber optic Internet download speeds depend on your connection. Not all fiber services are created equal, much like broadband. ... You can download more, faster, with fiber. Fiber Internet is more reliable than copper and less 'patchy' than Wifi. 9. Is fiber optic analog or digital?Digital signals can be transmitted long distances without degradation as the signal is less sensitive to noise. Fiber optic datalinks can be either analog or digital in nature, although most are digital. Both have some common critical parameters and some major differences. 10. How much data can a fiber optic cable transmit?A new fiber-optic system can carry 800 gigabits of data per second, a big step up from top speeds of 100 or 200 gigabits in today's data centers. You May Also Like:GPS and inertial sensors for driverless applicationsA New Technology for Advancing Opticals,Sensors Even Resistant SupercapacitorsSensors are Always In a State of Rapid Progress

Warm hints: The word in this article is about 2800 words and  reading time is about 15 minutes.     Lithium-ion batteries can be said to be the most mature and widely used new energy sources in the world at present, such as portable electronic products like mobile phones and computers, electric vehicles, electric tools, and energy storage projects. Especially the current Chinese government and other countries are investing to support the development of new energy vehicles and power battery industries. Looking ahead, the lithium industry has a long way to go, such as the development of high energy density systems. The problems of further reduction of cost, the resources recovery, and the utilization are in front of us.   This article will mainly explain what is a lithium battery, then introduce the current situation and future development of lithium-ion battery materials.       Catalog I. What is A Lithium Battery? II. How Does the Lithium Battery Work? III. Distinction Between Lithium-ion Battery & Polymer Lithium Battery IV. Types and Characteristics of Material Used in Lithium Batteries V. Application of Lithium Battery VI. Future Development of Lithium Battery FAQ I. What is A Lithium Battery?   "Lithium battery" is a kind of battery that takes lithium metal or lithium alloy as negative electrode material and using a non-aqueous electrolyte solution. In 1912, lithium-metal batteries were first proposed and studied by Gilbert N. Lewis. In the 1970s, M.S. Whittingham proposed and began to study lithium-ion batteries.   Because of the active chemical characteristics of lithium metal, the environmental requirements of the processing, preservation, and use of lithium metal are very high. Therefore, lithium batteries have not been applied for a long time. With the development of science and technology, lithium batteries have become the mainstream now.   Lithium batteries can be roughly divided into two categories: lithium metal batteries and lithium-ion batteries. Lithium-ion batteries do not contain metallic lithium and are rechargeable. The fifth generation of rechargeable lithium metal batteries was born in 1996. Its safety, specific capacity, self-discharge rate, and the ratio of performance to price are superior to those of lithium-ion batteries, which are now produced by a few companies in only a few countries due to their own high-tech constraints.   Li-ion batteries are secondary battery system in which two different kinds of lithium intercalated compounds that can be inserted and removed as positive and negative electrodes respectively. When charged, lithium-ions are removed from the lattice of cathode materials. After the electrolyte is inserted into the lattice of the anode material, the negative electrode is rich in lithium, and the positive electrode is poor in lithium.   When discharged, the lithium-ion is removed from the lattice of the anode material, and then inserted into the lattice of the positive electrode material after the electrolyte, so that the positive electrode material is extremely rich in lithium while the negative electrode is poor in lithium. In this way, the difference between the potential of the cathode material and the lithium-ion when inserted and removed from the lithium metal is the working voltage of the battery.   Li-ion battery is a new generation of green high-energy battery with excellent performance and has become one of the key points in the development of high-tech.   Li-ion battery has the following characteristics: high voltage, high capacity, low consumption, no memory effect, no pollution, small volume, small internal resistance, less self-discharge, and more cycle times.   Because of the above characteristics, the lithium-ion battery has been applied to many civil and military fields, such as mobile phones, notebooks computers, cameras, digital cameras, and so on.   II. How Does the Lithium Battery Work?   The charging and discharging process of lithium battery is realized by the removal and embedding of lithium-ion in the positive and negative electrode of the battery. The reaction equation of the lithium-ion battery with iron phosphate liquid as an example is as follows:   Charging: Discharging:   The electrode reaction of Li/PEO-LiClO4/Pan polymer lithium-ion battery is as follows:   Positive electrode reaction: Negative electrode reaction： The working schematic diagram of lithium battery: Schematic-of-the-lithium-ion-battery-working-principle   1. The positive electrode structure:  LiMn2O4( lithium manganate ) + Conductive agent (acetylene black) + adhesive(PVDF) + Collector negative ( aluminium foil )electrode   2. The negative electrode structure:  Graphite+ Conductive agent (acetylene black) + adhesive(PVDF) + Collector negative ( copper foil )electrode   3. Charging process: The battery is charged by the power supply, and the electron e on the positive electrode runs from the external circuit to the negative electrode. Positive lithium-ion Li+ "jumps" from the positive electrode to the electrolyte, "climb" through the winding hole in the diaphragm, then "swim" to the negative electrode and combine with the electron.    The reaction on the positive electrode is: LiMn2O4 ==Li1-xMn2O4+Xli++Xe (electron).  The reaction on the negative electrode is:  6C+XLi+Xe==LixC6   4. Discharging process When the battery discharges, the electron e on the negative electrode runs from the external circuit to the positive electrode. Positive lithium-ion Li+ "jumps" from the negative electrode to the electrolyte, "climb" through the winding hole in the diaphragm, then "swim" to the positive electrode and combine with the electron.    The reaction on the positive electrode is: Li1-xMn2O4+xli++xe (electron) ==LiMn2O4 The reaction on the negative electrode is: LixC6 == 6C+xLi+xe III. Distinction Between Lithium-ion Battery & Polymer Lithium Battery   As the following table: Electrolyte for Polymer Lithium Battery PolymerElectrolytePure solid polymer electrolyteGel polymer electrolytePAn, PPY, PA, PPPPEO, PPOPAN,PMMA,PVdF   As the following diagram: Different electrolytes are the main differences between lithium-ion batteries and polymer lithium batteries. Diagram IV. Types and Characteristics of Material Used in Lithium Batteries (This is a tutorial on the Lithium Battery Explorer provides an overview of Li-ion battery technology and the properties that are relevant to battery researchers.)   1.Lithium manganate (LMO) LMO, as a kind of lithium battery material with a long history, has high safety, especially strong resistance to overcharge, which is a prominent advantage.   Because of the good structural stability of lithium manganate, the amount of cathode material does not have to exceed the negative electrode in the design of the electric core.   In this way, the number of active lithium ions in the whole system is small, and after the negative electrode is filled, there will not be too many lithium ions in the positive electrode. Even if overcharge occurs, there will not be a large number of lithium ions deposited in the negative electrode to form crystallization. Therefore, the overcharge resistance of lithium manganate is the best in common materials.   In addition, its material price is low, and the production process requirements are relatively low. It is a relatively early widely used cathode material.   But it also has obvious defects. The elevated temperature property of spinel lithium manganese oxide is poor. The existence of oxygen defect makes the core prone to capacity decay at the high voltage stage, at the same time, the cycle use at high temperature would cause a similar capacity decay. The reason is that the trivalent manganese ion which causes the disproportionation effect. The main way to prevent high-temperature attenuation is to reduce the trivalent manganese.   Lithium manganese, limited by its high-temperature performance, is generally not used in high-power or high-temperature environments, such as high-speed passenger vehicles, plug-in cars, and so on. But for electric buses, local logistics vehicles, and so on, lithium manganese is completely competent.     2. Lithium iron phosphate (LFP) The advantages of lithium iron phosphate are mainly reflected in its safety and cycle life. The main determinants are the olivine structure of lithium iron phosphate, which, on the one hand, leads to the lower ion diffusion capacity of lithium iron phosphate. On the other hand, it also has good high-temperature stability and good cycle performance.   The disadvantages of lithium iron phosphate are also obvious, such as low energy density, poor consistency, and poor low-temperature performance.     a) The low energy density is determined by the chemical properties of the material itself. A lithium iron phosphate macro-molecule can accommodate only one lithium-ion.   b)The consistency, especially poor batch stability, is related to not only the level of production management but also its own chemical properties. Lithium iron phosphate is one of the more difficult materials for the preparation of cathode materials for lithium-ion batteries.   The difficulty of consistency and uniformity in this chemical reaction raises another problem at the same time: The impurity of iron and iron in the lithium iron phosphate material always exists, which brings hidden trouble to the battery.   Lithium iron phosphate battery, because of its high safety, although The energy density part affects its range of use., but it is still the main power lithium battery variety of electric vehicle in our country at present, especially buses involving the safety of a large number of people, the national police enforce the use of lithium iron phosphate batteries.     3.Ternary lithium The ternary lithium cathode material synthesizes the advantages of LiCoO2、LiNiO2 and LiMnO2 and forms a synergistic effect within the same core. It combines three requirements of stability and activity of material structure and lower cost, which is one of the three main cathode materials with the highest energy density. The low-temperature performance is also obviously better than the lithium iron phosphate battery.    The higher the content of Ni in the three elements, the higher the energy density of the core and the lower the safety of the core will be. In practical application, the proportion relation of three kinds of materials in the electric core has been changing with the passage of time. The pursuit of energy density is higher and higher, so the proportion of Ni is higher and higher.   The most mentioned disadvantage of ternary material is safety. During the process of thermal runaway, the side reaction product contains a lot of gas, which greatly improves the risk of accident and the ability to spread.   Secondly, the cycle life of ternary materials is also a bottleneck, which has not reached the level of lithium iron phosphate. Last but not least, due to the special microstructure of ternary materials, it is not suitable for high-pressure compaction operation, thus the popular way to increase the energy density is not applicable to it.   The market share of ternary materials is gradually expanding, mainly driven by the pursuit of vehicle range. To catch up with or even surpass that of fuel vehicles, electric vehicles must have as much power as possible in a limited space.   This makes energy density particularly important. The improvement of the safety performance of the battery itself and the improvement of system monitoring and handling accident capability will also promote the expansion of the lithium ternary battery market.   V. Application of Lithium Battery   1. Lithium Iron Phosphate is the most suitable cathode material for Power Battery   After introducing the Types and characteristics of Lithium batteries above, now we will discuss about the most suitable cathode material for power supply.    Since 1996, when the Japanese NTT first exposed lithium iron phosphate cathode materials of olivine structure, John.B.Goodenough professor at Texas University also reported the characteristics of reversible intercalation and removal of lithium from LiFePO4 in 1997.   Since then, lithium iron phosphate has gradually become one of the low-cost, multi-element, and environmentally friendly cathode materials. Compared with traditional cathode materials, spinel LiMn2O4 of spinel structure and layered LiCoO2, the LiMPO4 of olivine structure is extremely stable.   The bond with oxygen is very strong, it will not explode because of the short circuit, the capacity is up to 170 mAh / g, the raw material is more extensive and the price is lower. Because of the similar structure of LiFePO4 and FePO4, the crystal structure of LiFePO4 has almost no rearrangement after the release/embedding of lithium-ion.   Therefore, LiFePO4 has better cycling performance, lithium-ion can enter and exit freely and can charge and discharge more than 1,000 times. It is also reported that lithium iron phosphate can be modified more than 10,000 times.   According to the following picture: Performance comparison of Lithium batteries with different cathode Materials.   Performance comparison Lithium iron phosphate is the most ideal cathode material at present. In comparison, the biggest problem of LiCoO is that it is easy to explode at a low temperature of 150C, and its cost is high (cobalt price is about 500,000 yuan/ton, and the price of LiCoO containing 60% cobalt will be over 400,000 yuan/ton). Also, it has a short cycle life.   The safety of lithium manganese oxide is much better than that of lithium cobaltate, but the cycle life in a high-temperature environment is even worse than that in a high-temperature environment(500 times).   With the advantages of high discharge power, low cost (about 18.3 million yuan/ton), rapid charging and long cycle life of more than 1000 times, the high stability of high temperature and high heat environment, and the good safety performance, lithium iron phosphate is the most ideal lithium cathode material for power vehicles.   At present, though the lithium iron phosphate battery is developing rapidly in China, there are several problems, including patent hidden trouble, low conductivity, and low capacitance, poor low-temperature performance, and low yield. VI. Future Development of Lithium Battery   Polymer Lithium Battery: one of the Future Development directions In addition to pure solid or gel polymer electrolytes, the principle and charge-discharge process of polymer lithium-ion batteries are consistent with those of liquid lithium-ion batteries.   Polymer lithium battery features include plastic flexible, more stable, safer, and less flammable, longer cycle life, higher energy density, high volume utilization(10-20% higher than lithium-ion batteries), no need to use traditional diaphragm materials, and easier for large scale production.   Polymer electrolyte is a kind of functional polymer material with ionic conductivity in solid-state which is formed by complexation of strong polar polymer and metal salt through acid-base reaction. Pure solid-state electrolyte dissolves lithium salts such as LiPF6, LiClO4, and LiBF4 in polymer bulk such as PEO and PPO as solid solvents. Gel electrolytes are electrolytes in a gel state by mixing more liquid solvents with polymer bulk.   Because there is no liquid flowing in the electrolyte, there is no leakage of the battery, so the problems such as burning and explosives are avoided. In order to reduce the thickness of the battery, a polymer lithium battery is usually packaged with aluminum plastic film with a thickness of only 0.1 mm, so it has a higher specific capacity than the ordinary lithium-ion battery.   FAQ   1. What is the difference between a lithium battery and a lithium ion battery? Lithium batteries feature primary cell construction. This means that they are single-use—or non-rechargeable. Ion batteries, on the other hand, feature secondary cell construction. This means that they can be recharged and used over and over again.   2. What are the disadvantages of lithium ion batteries? Despite its overall advantages, lithium-ion has its drawbacks. It is fragile and requires a protection circuit to maintain safe operation. Built into each pack, the protection circuit limits the peak voltage of each cell during charge and prevents the cell voltage from dropping too low on discharge.   3. Why is lithium ion the best battery? Li-ion batteries are able to be recharged hundreds of times and are more stable. They tend to have a higher energy density, voltage capacity and lower self-discharge rate than other rechargeable batteries. This makes for better power efficiency as a single cell has longer charge retention than other battery types.   4. What is the life of lithium ion battery? about two to three years. The typical estimated life of a Lithium-Ion battery is about two to three years or 300 to 500 charge cycles, whichever occurs first. One charge cycle is a period of use from fully charged, to fully discharged, and fully recharged again.   5. Is it good to fully discharge a lithium ion battery? Lithium-ion batteries should not be frequently fully discharged and recharged ("deep-cycled"). You may need to discharge it fully occasionally to recalibrate the capacitiy measuring electronics in the accumulator. Every 30 cycles or so should be enough.   6. How do I know if my lithium ion battery is bad? If the battery is dead or at the end of life, then it won't take charge anymore. If the battery is dead or at the end of life, the battery will swell a bit. The battery starts to heat up very quickly is also one of the indication that your battery is at the end of life.   7. Is there an alternative to lithium-ion batteries? Zinc-ion: A competitive alternative to lithium-ion for stationary energy storage. Lithium-ion batteries are the leading battery technology for both electric vehicles (EVs) and the renewable energy industry.   8. Do lithium ion batteries go bad if not used? Lithium Ion batteries "go bad" when they are stored in discharged state. It is all about battery voltage. If voltage is too low - undesireable chemical reactions will happen and battery will degrade. If battery is not empty and not used for long time - it will be fine.   9. What temperature is bad for lithium batteries? At temperatures above +60°C the Li-ion battery loses capacity constantly and thus performance capability.   10. At what voltage is a lithium ion battery dead? 3.4V. The voltage starts at 4.2 maximum and quickly drops down to about 3.7V for the majority of the battery life. Once you hit 3.4V the battery is dead and at 3.0V the cutoff circuitry disconnects the battery (more on that later. You may also run across 4.1V/3.6V batteries.     You May Also Like: How to Learn Analog Circuit Design Topological Materials are a Promising Material For Boosting Thermoelectric Generation Efficiency Use Polymer Films Material to Make Solar Cell Learn Some Basic Knowledge about Capacitor Voltage Transformer The First Full-Size IBC Bifacial Solar Module in the World

Warm hints: The word in this article is about 3000 words and  reading time is about 15 minutes.   This paper is mainly about how to learn analog circuit design. An analog circuit is a circuit used to transmit, transform, process, amplify, measure, and display analog signals. Analog signals refer to continuously changing electrical signals. Analog circuit is the basis of the electronic circuit, which mainly includes amplifier circuit, signal processing, and processing circuit, oscillation circuit, modulation and demodulation circuit, and power supply.    Analog circuit   Catalogs   I. What’s the Engineering Thinking in Analog Circuit II. Commonly Used Semiconductor Devices III. Negative Feedback Basic Concepts IV. Operational Amplifier Development V. Conclusion FAQ I. What’s the Engineering Thinking in Analog Circuit   Analog circuit is a very important profession, and difficult for people to learn. Now, let me talk about my understanding of the analog circuit. When it comes to the understanding and application of analog circuits, I’ve done some projects and participated in competitions. The analog circuit is an engineering course, and the earning focus is to master the engineering ideas. It’s better to put it into practice, instead of only doing the exams. What is the engineering idea? Encyclopedia +explains as this: "Engineering is the application of science and mathematics. Through this, natural material and energy characteristics can be made into efficient, reliable, and human-friendly products flow through a variety of structures, machines, products, systems, and processes, with the shortest Time, and less refined manpower, so the concept of engineering comes out and it has evolved into an independent discipline and skill. "For example, in analog circuits, there is a very Important engineering thinking - approximation.   In high school physics class, we learn a lot of circuits are ideal circuits. The wire resistance is always 0, the transformer efficiency is 100%, the ideal voltmeter resistance is infinite, the ideal ammeter resistance is 0, and so on. You can see that many times the calculation in an analog circuit will often omit one or two smaller items and use the equal sign instead of the equal sign directly.   Why use an approximation? To put it plainly, people’s understanding of nature in human science is not comprehensive enough to describe the natural phenomenon with absolute precision. Or human’s understanding is limited. By the means of approximation, people have not only achieved an obvious effect on solving the problem but also greatly simplifies the procedure and saves time and effort. With this thought, many achievements have been made in human science, which has also proved its reliability.    Summary Mold itself is a very complex subject, and the molding course is just one of the most basic things. Analog Circuit Meaning is the electronic circuit that processes analog signals. Most of the signals in nature are analog signals, and they have continuous amplitude values, such as the sound signal when speaking. Analog circuits can be such signal processing (of course, need to be converted into electrical signals), such as amplifier to amplify the sound signal, the radio can send analog sound signals, image signals. It can even be assumed that all circuits are based on analog circuits (even for digital circuits, the underlying principle is based on analog circuits). Its importance is self-evident.    Due to the rapid development of digital circuits and programmable devices, many superior features are demonstrated. Many electronic devices are slowly digital but still can not do without analog circuits. The most important analog circuit devices, non-semiconductor devices are none other than. The most basic and commonly used semiconductor devices are diodes, transistors, FETs, and operational amplifiers. II. Commonly Used Semiconductor Devices   The diodes have many roles. Ordinary diodes can be used for rectification, light-emitting diodes can be used for indicator and lighting, regulators can be regulated, varactor diodes can be used for signal modulation. The mold course related to the part of the diode is relatively simple. And many characteristics of the FET are similar to the transistor, so we often explain transistor or amplifier instead.    The basic function of the transistor is to enlarge. The transistor constitutes a variety of circuits because of its features, reflecting a lot of engineering ideas. The transistor-based circuit is the amplifier whose input sound is small, the output sound is great. Amplifier output and the input voltage (or current) ratio is called magnification, also known as gain. For a voltage, if the time for the horizontal axis, voltage vertical axis for mapping, the graph is the voltage waveform. If an amplifier with a gain of 5 inputs a constant voltage of 1V (the waveform on the left is shown below), the output should always be 5V (the waveform is shown in the middle figure below), neither changing with time nor changing with temperature And the input voltage exactly the same shape. However, if the magnification is unstable and constantly changing, the original input signal will be distorted (as shown on the right), and the signal may change from a horizontal straight line to a curved line. This waveform change is called distortion. Voltage waveform   III. Negative Feedback Basic Concepts   The basic concept of negative feedback makes some very powerful people find a good way: negative feedback. What is negative feedback? "Feedback refers to the output of the system is returned to the input and affect the input, thus affecting the overall system output Feedback can be divided into positive feedback and negative feedback is to make the output and input the opposite effect, the system Output tends to be stable. "The above explanation is hard to make sense. I have two examples. When playing the inverted pendulum, we propped up an inverted wooden stick by hand. When the wooden stick was tilted in one direction, we offset the change by moving the hand to the direction of the stick so that the stick could be in our hand's balance.    When I was in high school, I often had a monthly test. I found that some of my classmates had a habit of starting a good study when a test score was poor and going up next time. When the test was better, the next month will be relaxed, so results will come down again, so again and again. Both of these examples illustrate that negative feedback can make the system more stable. We ignore the specific circuit, only draw a simple diagram to illustrate how the transistor amplifier uses the negative feedback. The triangle below shows a transistor consisting of an amplifier, the magnification is A, the input is I, the output O = I * A, because the magnification A instability, so the output waveform will be distorted.  Negative feedback   Some devices have been added to the circuit as follows. The purple circle is the adder, combined with the purple "+", "-" symbol that its output Y = (+ I) + (- X) = I-X, in the actual circuit with the resistance can be achieved; Block F is the feedback device, which means that the signal is taken out from the output O and multiplied by F to get X, so X = O * F, where F <1 (this part can be realized by resistance in the actual circuit). Triangle refers to the amplifier A, mainly composed of transistors, meeting O = A * Y, and A magnification is unstable, easy to be disturbed. Add a feedback device   You can list the equations: Y = I-XO = Y * AX = O * F to calculate the gain of the entire circuit: Formula   If the magnification A is very large, while F is not small, A * F 》》1 symbol "》》" suggests far greater than the approximate idea. The entire circuit magnification: Formula   IV. Operational Amplifier Development   1.Working principle of operational amplifier Because the feedback device can be realized by the resistance, the resistance value of the ordinary resistance is not easily disturbed by the outside world, so the value of F is very steady, so the magnification of the whole circuit is very steady. We succeeded in solving the stability problem of the transistor by negative feedback. We can see here that the feedback part and the amplification part form a ring, so the amplification of the whole circuit is called the loop gain or the closed-loop gain. Before adding the feedback, the amplification of circuit A is called the open-loop gain. Due to the negative feedback, the stability of the circuit is improved, but there is also a cost: Because the AF 》》1, then "A》》1 / F" open-loop gain is much larger than the closed-loop gain, which means the amplifier gain is greatly reduced. But in general, this is worth it for stability. Operational amplifier In the above circuit, in order to actually create a large open-loop amplifier gain A, often with multi-stage transistor amplifier in series design.   Because the high demand for such high-gain amplifiers is very common, so some people in history put them into a finished circuit board module. This is used directly as a component on the line when needed because it’s very convenient. This is the original op-amp, which is referred to as op-amp. The development of integrated circuits makes a large number of transistor components integrated into a small chip possible, so the common integrated operational amplifier turns up today.    The "op-amp" is named for its mathematical operation originally used to simulate computers. Although now widely used digital computer is no longer used to calculate the operational amplifier, but the name still retained. Today, op-amps play an important role in analog circuits and have also become one of the focuses of the analog circuit. The op-amp has virtual short and virtual interrupt characteristics. Usually, op-amp has two inputs U + and U-, an output Uo, between them to meet Uo = A * (U + -U-) op-amp open-loop gain A often up to dozens Million ~ millions, but the op-amp output voltage limited by the supply voltage can not exceed the supply voltage. So the op-amp input-output relationship similar to the shape below. In the figure, the horizontal axis is (U + -U-) and the vertical axis is Uo. Op amp input - output In the middle of a straight line, the op-amp is in the normal state of amplification, called the linear region, meeting Uo = A * (U + -U-). When the absolute value of the input becomes slightly larger, the output will be power limited, no longer satisfying the above relationship. The value of Uo is usually slightly smaller than the supply voltage range (note that the op-amp can be dual supply, that is the supply voltage range can be afloat between a negative value and a positive value), which is called the non-linear region. Rail-to-rail op-amp output can reach the power supply voltage.   When the operational amplifier in the linear region, the Uo value is very limited, but A large. So U + -U- = UoA ≈ 0 or U + ≈ U-. At this time, the positive and negative op-amp input voltage is almost equal, like a short circuit similarly, which is called a short circuit. So only when the operational amplifier in the enlarged area will have "virtual short" characteristics, rather than the inherent properties of the op-amp. On the other hand, due to the internal structure of the op-amp, its input impedance is large.    The input impedance can be simply understood as: the input impedance = input voltage/input current input impedance, which means that the op-amp input with only a small current can work properly. Because of this, an op-amp can be used for some weak current detection, such as the human brain, myoelectric wave, whose maximum voltage is only a few mV, the current value is very small. This feature of the op-amp is called a virtual interrupt, meaning that there is almost no current flowing into the input like the open circuit. Different from the short circuit, a virtual interrupt is the inherent properties of the op-amp, which will not change with the circuit.   2.Op amp non-ideal characteristics   The op amp's non-ideal characteristics of the op-amp by the transistor composition. Obviously, like the transistor, there will be many undesirable characteristics. The actual operational amplifier will not fully meet the short virtual fault characteristics. Its normal work needs input current input, which is called the input bias current.    The same op-amp input offset voltage, input offset voltage, input offset current, and other non-ideal parameters. These non-ideal characteristics, such as the input bias current is small, sometimes will have a great impact on the circuit, resulting in the circuit does not work. Therefore, there are some ways to reduce the impact of these factors. In practical applications, the non-ideal characteristics of the op-amp are a very important issue. There are many ways to eliminate the non-ideal characteristics of the op-amp, but not introduced here.    Other cores of the molding course are the transistor and op-amp. Around these devices, the molding course will explain a variety of circuits, including the calculation of the amplifier circuit analysis, multi-stage amplifier circuit, the amplifier frequency characteristics, the idea of feedback, power amplifier circuit, comparator, oscillator, integrator, differentiator, waveform generation, Signal processing, filter, integrated power supply circuit and so on. When comparing op-amp and transistor In the actual design of the circuit, the op-amp will be more than the transistor. Because many of the features of op-amps are better than triodes, the circuit design is simple, and the cost of op-amps is often not too high.   Many times you can achieve the same effect with the transistor and op-amp and lower cost of each op-amp. Because op-amps integrate a large number of transistors, the average cost per transistor is very low. For example, a conventional audio pre-amplifier can be handled with a universal op-amp. and if you use the transistor, you may need more transistors, and the human cost during design is far higher than the op-amp program. Of course, the transistor has its advantages.    In some very simple circuits, the stability of the magnification is not strictly required, one or two transistors can accomplish. And triodes are often used to save costs. In addition, in some extreme conditions, such as working in high-frequency and high-power environments (such as RF signal transmitting circuits), a well-designed triode circuit will perform much better than an op-amp, or at a much lower cost. Even in some conditions, only the transistors can be completed, then you need to choose the transistor to build the circuit.   This video give a detailed explanation about analog circuit: Analog Circuits Lecture V. Conclusion   Analog circuits are a very complex discipline that involves more than knowledge written in books. Books are generally introduced in accordance with the principle of work, simplifying a lot of difficulties to understand, but in reality, more factors must be considered. So the gap between the actual circuit and the book is very large. Such as triangular wave generator built with an op-amp introduced in analog circuit books usually can not work in all likelihood. However, the main principle of the actual circuit is the same as the book description. Therefore, the design of analog circuits often requires a lot of experience, for there are many things that can not be explained and even difficult to calculate. I hope this article can help you learn more about analog circuits. FAQ   1. What is meant by analog circuit? The Analog electronic circuit includes an analog signal with any continuously changeable signal. While working on an analog signal, an analog circuit alters the signal in some manner. Analog circuit can be used to convert the original signal into some other format such as a digital signal.   2. What is the difference between digital and analog circuits? Analog Circuits and Digital Circuits is a classic way of differentiating between two types of electronic circuits based on the signals they process. To put it in simple words, Analog Circuits deals with continuous analog signals whereas Digital Circuits deals with discrete digital signals.   3. Where are analog circuits used? Analog circuits represent key components of communications and other systems in widespread, growing commercial use. High-speed transistors are essential to the operation of such circuits.   4. Is digital cheaper than analog? If you are looking at the straight-up module cost an analog vs. a digital version, then yes, the analog module will likely be a cheaper solution. However, if you look at the total cost, or the “value” of the digital module versus an analog solution, then digital will in fact be “cheaper”.   5. What is analog design? Analog design is part of integrated circuit design and focuses on signal fidelity, amplification and filtering. Those who perform the function of analog design are qualified electrical engineers.   6. Why is analog design difficult? Ask most engineers and they would tell you why: analog design is harder than digital, and requires more knowledge and more factors to consider such as a deep understanding of efficient power, precision measurement, wireless connectivity, and reliable circuit protection.   7. Which is better analog or digital design? Analog circuits can be precise, elegant design with various components with very simple. For example, two resistors joining to make a voltage divider. Generally, Analog circuits are much more complex to design compared to which complete the same task as digitally.   8. What is the tool used for analog circuit design? A suite of web tools to help you design signal conditioning circuits faster: Analog Filter Wizard, Precision ADC Driver Tool, Photodiode Wizard, In Amp Diamond Plot, Direct Digital Synthesis Simulator, and Virtual Eval.   9. How hard is circuit design? Circuit design is a lot like any other learned skill, you start with the basics. These basic circuits can be learned in a few days. ... So yes, it can be very difficult to reach a high level of design expertise and you never really master it because the art continues to evolve.   10. How does circuit design work? Digital electronic circuit design takes the electrical signals in the form of discrete values. The data are represented in the form of zeros and ones. Digital circuits extensively use transistors, interconnected to give create logic gates that provide the function of Boolean logic.   You May Also Like:   Look Forward to the Future of Semiconductor GaN High-Electron Mobility Transistor Power Amplifier Trojans are everywhere even the hardware Remote Electronic Transport Promote Organic Photovaltaic Power Generation Make Next-Gen of Computer Be Faster,Better, More efficient Some suggestions about protecting transformers  

Warm hints: The word in this article is about 2500 and  reading time is about 12 minutes.SummaryIndustrial robot is a multi joint manipulator or a multi degree of freedom machine tool for industrial field. It can automatically execute work, and is a machine that realizes various functions by its own power and control ability. It can accept human command or run in accordance with pre programmed programs. Modern industrial robots can also act according to the principles and guidelines formulated by AI technology.CoreIndustrial RobotsCategoryRobotKeywordsIndustrial robots;RobotContentA comprehensive analysis of industrial robotsCatalogs CatalogsI.What is industial robotsII.Composition structureIII.Types of industrial robotsIV.Industrial robot industrial chain analysisV.Data AnalysisVI.The development trend of robot in the next 10 yearsVII.Human-computer cooperation promotes the popularization of robots and the beginning of the integration of robotsVIII.Machine vision and deep learning make robots more Intelligent IntroductionI.What is industial robotsIndustrial robot is a multi joint manipulator or a multi degree of freedom machine tool for industrial field. It can automatically execute work, and is a machine that realizes various functions by its own power and control ability. It can accept human command or run in accordance with pre programmed programs. Modern industrial robots can also act according to the principles and guidelines formulated by AI technology.II.Composition structureThe industrial robot is composed of three basic parts: the main body, the driving system and the control system. The main body is the seat and the actuator, including the arm, wrist and hand, and some robots and a walking mechanism. Most industrial robots have 3~6 motion degrees of freedom, of which the wrist usually has 1~3 motion degrees of freedom. The driving system includes the power plant and the transmission mechanism to make the actuator produce the corresponding action. The control system sends out instructions to the driving system and the actuator according to the input program and controls it.III.Types of industrial robots1. Mobile Robot(AGV)A type of industrial robot, which is controlled by a computer, and has the functions of mobile, automatic navigation, multi sensor control, and network interaction.Widely used in machinery, electronics, textile, tobacco, medical, food, papermaking industries such as flexible handling, transmission and other functions, is also used in automated warehouse, flexible manufacturing system, flexible assembly system (with AGV as the assembly platform; at the same time activities) in the station, airports, post office sorting items as transport tool.2. Spot Welding RobotIt has the characteristics of stable performance, large workspace, fast speed and strong load capacity. The welding quality is obviously better than manual welding, which greatly improves the productivity of spot welding operation.It is mainly used for the welding of the vehicle, and the production process is completed by the major automobile main plant. Enterprise international industrial robot with long-term cooperation between the major automobile enterprises, provide all kinds of welding robot unit products to the large car production enterprises and the welding robot and vehicle production line matching form into Chinese, occupy the market leading position in the field.3. arc welding robotIt is mainly used in welding production of all kinds of automobile parts. In this field, the major international industrial robot manufacturing enterprises are mainly to provide unit products to complete equipment suppliers.4.Laser processing robotLaser processing robot is the application of robot technology to laser processing, and a more flexible laser processing operation is realized through high precision industrial robot.5. Vacuum robotA robot working in a vacuum environment is mainly used in the semiconductor industry to realize the transmission of the wafer in the vacuum chamber. Vacuum manipulator is difficult to import, restricted, large consumption and versatility. It has become a key component that restricts the R & D Progress of the semiconductor equipment and the competitiveness of the whole product. Moreover, the overseas scrutiny of Chinese buyers is part of the catalogue of banned products. Vacuum manipulator has become a serious problem that restricts the manufacturing of semiconductor equipment in China. The technology of direct drive vacuum robot belongs to the original innovation technology.6. Clean RobotAn industrial robot used in a clean environment. With the continuous improvement of production technology level, its production environment is increasingly demanding. Many modern industrial products are required to carry out in a clean environment. Clean robots are the key equipments for production under clean environment.  DetailIV.Industrial robot industrial chain analysisThe industrial robot industry upstream core components, the main reducer and control system, which is equivalent to the robot's "brain", is in the middle reaches of the robot, the robot is the "body", downstream systems integrator, domestic enterprises are concentrated in this link.Industrial chain analysis of industrial robots in ChinaThe upstream parts industry of China's industrial robots is mainly reducer, servo motor, frequency converter and controller. Among them, the proportion of reducer, servo motor and servo system in industrial robot cost is larger, which is 39% and 28% respectively, and the proportion of noumenal manufacturing is 22%.Although the speed reducer, servo system for industrial robots in a large proportion of the cost, but the domestic reducer, servo motor and other key parts of the development relative lag, low level of technology, poor product stability, compared with foreign products, there are many gaps, resulting in domestic industrial robot speed reducer, servo motor and other components mainly rely on imports, domestic industrial enterprises the robot production cost is high, less competitive. The imported gear reducer mainly ABB, Harmonic, Sumitomo nabok, and other brands, the main servo motor Yaskawa, KUKA, Matsushita, MITSUBISHI and other brands.The sales of industrial robots are mostly done through direct marketing channels, with the majority of the system integrators. At the same time, industrial robots can also be sold by distributors, agents, traders, engineering providers and other non direct sales, and foreign brands enter the Chinese market generally through the form of agents. The core components are generally purchased by traders and agents.The industrial robot industry is mainly downstream users of electronic and electrical, automotive, plastics and rubber, chemical and other fields, mainly used for handling, packing, palletizing, welding, cutting, spraying, and with labor costs increased gradually, and constantly improve the level of industrial automation, industrial robot application areas gradually expand, use gradually increased.V.Data AnalysisThe list of RBR50 in 2016 covers 11 countries. The distribution is as follows: Canada (3), China (3), Denmark (1), Germany (3), India (1), Israel (1), Japan (9), South Korea (1), Switzerland (1), Britain (1), and the United States.The list of RBR50 in 2015 covers a total of 11 countries. The national distribution is as follows: Canada (3), Denmark (1), France (1), Germany (8), Japan (9), South Korea (1), Holland (1), Switzerland (3), Taiwan, China (1), Britain (1), and the United States.By comparison, the United States in 2016 the new list of 5 companies, 5 companies failed in Germany, Switzerland retained only 1 companies in France and Holland is completely failed. At the same time, there are some new faces, Israel, India and China.It can be seen from the RBR50 list that the European robot industry has a serious downward trend and needs to be revival. The GreyOrange company in India is catching up with the trend of the rapid development of the logistics and transportation industry. Its flagship mobile robot will have great potential in the Asian market. Britain's Delphi, SoilMachineDynamics, OpenBionics three companies listed, surprisingly, OpenBionics small company has been on the list for two consecutive years; Canada continues to rely on Clearpath, Robotiq and new TitanMedical three companies to maintain strength.2015 global 30% industrial robots are sold to the Chinese marketWhether it's made in China or raised in 4, the 4 concept indicates that China's manufacturing industry is moving towards the direction of intellectualization and mechanization. The rapid development of industrial robots is one of the most representative industries.Strong sales growthIn 2015, the sales of China's market exceeded 75000 units, up 36.6% from the same period, and 3 robots were sold in the world, and 1 were sold to China. China Industrial Robot MarketIn 2015, the sales of industrial robots in the Chinese market accounted for about 30% of the world  AnalysisVI.The development trend of robot in the next 10 yearsThe robot itself in the overall change, to a more secure and easy to use, more conducive to popularization, more intelligent direction. The next three trends in the next ten years can solve the industry pain points, promote the real popularity of robots, and also contain huge investment opportunities.The general software platform reduces the threshold of the robot industryThe main internal power of the rapid popularization of computers and smart phones is the common operating system and application software, and robots are the same. The operating system, middleware, and programming language used by different robot vendors are different, which increases the cost of use and the scope of robot application. The general software platform (operating system) is a solution to this problem, making use of robots as convenient as smartphones.A common development platform for robot softwareThe general software platform greatly reduces the development threshold of robots. The mature software in the community can be directly brushed into the robot's use. In the future, with 3D printing technology, small businesses and even individuals will have the chance to become robot developers. The opportunity is that there may be two development or excellent applications for a ROS system, a "burst" like a smart phone APP.VII.Human-computer cooperation promotes the popularization of robots and the beginning of the integration of robotsHuman-machine cooperation is a new form of industrial robot development. It combines human intelligence and robot efficiency together to complete operations. In a word, human is directly manipulating robots with "hands". Human-computer collaboration is an inevitable choice for robot evolution. It is characterized by safety, ease of use and low cost. Ordinary workers can operate it like electrical appliances.According to the US ABIResearch report, from 2015 to 2020, the market share of cooperative robots is expected to increase by 10 times, from close to 95 million US dollars to over 1 billion US dollars. It will be driven by the following three main markets: electronic manufacturing and electronic intelligence, small and medium enterprises and enterprises seeking robot optimization solutions.The structure of the cooperative robot is simple, and the function is realized mainly through the integration of software. The main components of the hardware are spherical joint, reverse driving motor, force sensing / visual sensor and lighter material. The core components of the traditional reducer will not be the key in the future. At present, the cooperation robot is in the market introduction stage, the cost is still high, the efficiency is low, and the utilization is not satisfactory. The main robot manufacturers have launched various kinds of cooperative robots to seize the entry, and the domestic enterprises have the opportunity to run together with foreign capital. SIASUN, AIFUTE, Ao Bo in 2015 have launched a collaborative robot intelligent.VIII.Machine vision and deep learning make robots more IntelligentArtificial intelligence is first applied to the field of industrial robots, mainly machine vision and deep learning.Machine vision is a key factor in the transformation of an existing robot from an automatic device to an intelligent machine. The first is used as an auxiliary tool for the robot, improve the flexibility and feedback of the work environment, mainly used for guiding and positioning, detection and recognition, with the development of industrial data and deep learning, the future will enable the machine vision to become the leading intelligent production system, make a decision and pre judgment.In 2014, the scale of the global machine vision continued to rise to up to $3 billion 670 million. Mainly in North America, Germany, Britain, Japan, China and other regions and countries, China accounts for 8.1%, and the global market is expected to reach US $5 billion by 2018. 2007-2018 year global machine vision market scale ConclusionThis is an era of "made in China" to the transformation of "China's intellectual creation". Robots replace human beings to do repetitive things, so that we can advance technological progress, and talents will enter new industries, and everyone's production value will be improved.Not long ago, Foxconn, the world's largest producer, has rounded the horn of "machine replacement" to many enterprises on the road of automation. We can boldly predict that in the next ten years, the industrial robot market will be broader. "Machine replacing human" will go deep into all walks of life. Automation transformation will also become the goal of many enterprises.  Book RecommendationRise of the Robots: Technology and the Threat of a Jobless Future Paperback – July 12, 2016What are the jobs of the future? How many will there be? And who will have them? As technology continues to accelerate and machines begin taking care of themselves, fewer people will be necessary. Artificial intelligence is already well on its way to making "good jobs" obsolete: many paralegals, journalists, office workers, and even computer programmers are poised to be replaced by robots and smart software. As progress continues, blue and white collar jobs alike will evaporate, squeezing working- and middle-class families ever further. At the same time, households are under assault from exploding costs, especially from the two major industries-education and health care-that, so far, have not been transformed by information technology. The result could well be massive unemployment and inequality as well as the implosion of the consumer economy itself.The past solutions to technological disruption, especially more training and education, aren't going to work. We must decide, now, whether the future will see boad-based prosperity or catastrophic levels of inequality and economic insecurity. Rise of the Robots is essential reading to understand what accelerating technology means for our economic prospects-not to mention those of our children-as well as for society as a whole.--Martin Ford  (Author)  Relevant information about "A Comprehensive Analysis of Industrial Robots"About the article "A Comprehensive Analysis of Industrial Robots", If you have better ideas, don't hesitate to  write your thoughts in the following comment area. You also can find more articles about electronic semiconductor through Google search engine, or refer to the following related articles. Living Insect-Machine Hybrid Robot--Swarming Search and RescueMake Robots Walk NaturallyThe Future Market of Industrial Robots in China will Be Far Beyond ImaginationEngineers from MIT Developed A Tiny, Affordable Robotic Device That Can Detect Water LeakThree Fingers Robotic Hand with Specialized Sensors can Estimate Size and Shape of ObjectsA New, Electronic Skin Microsystem Enables People Tracks Their Heart Rate And Other Health Index   

Warm hints: The word in this article is about 2000 and  reading time is about 10 minutes.SummaryIn ten years ago,the average selling price of industrial robots is about 500 thousand;however, the price is now four large family robot 15-20 million,Eft, and other domestic price slightly lower than the eston robot four family, economic type of pure domestic robot (terminal sales price of about 80 thousand. It is estimated that in the future, the average price of industrial robots will be reduced to less than 50 thousand with the localization of the spare parts and other parts.  CoreIndustrial RobotsCategoryRobotKeywordsindustrial robots;cloud service robotContentFuture market prediction about industrial robots in China Catalogs CatalogsI. The Statistics of Industrial robots Sales in recent yearsII.One of the development trends of industrial robots: more flexibleIII.The two development trend of industrial robots: low cost economy OntologyIV.Prediction about Industrial Robot IntroductionBefore we read the artcle,let's see a video about "MIT cheetah robot lands the running jump".In a leap for robotic development, the MIT researchers who built a robotic cheetah have now trained it to see and jump over hurdles as it runs — making this the first four-legged robot to run and jump over obstacles autonomously.  I. The Statistics of Industrial robots Sales in recent yearsWe know that science and technology are constantly growing after see the above video. According to IFE statistics,the global industrial robot sales exceeded $13 billion 200 million (plus integration part, system on the industrial robot market is about $50 billion) in 2016,with the major economies of the global industrial automation,robot using density increase. What’s more, IFR predicted that the world robot sales were 34.7, 37.8, 43.5 and 522 thousand respectively when in 2017-2020 years,and CAGR reached 15.4% in the next 4 years.Prediction of the sales of industrial robots in the global marketAccording to statistics, in 2016, domestic industrial robot sales hit a new high, reaching 87 thousand units, and by December 2017, China's industrial robot output reached 131 thousand units (set), an increase of 51% over the same period, and sales volume is expected to continue to grow this year. According to the prediction of IFR, 2018-2020 years of domestic robot sales were 16, 19.5, 238 thousand, 22% to 3 years in the future CAGR.Prediction of the sales of industrial robots in the global market In 2017, the domestic industrial robot market rapid growth for two reasons, one is the demand of the robot driven by 3C's apple, the other is the general manufacturing robots used in large-scale attempt, many general manufacturing enterprises, such as the winery, an order in more than 100. The difficulty of recruiting workers and the high cost of recruiting workers are becoming more and more common, which makes the demand for robots increase.At present, the domestic robots are mainly used in the general manufacturing industry other than cars and 3C. This year, not only foreign brands, but also domestic industrial robots.Domestic industrial robot sales structure in 2016 and over the yearsAccording to the National Bureau of statistics, China has 50 million manufacturing workers in each industrial robot instead of 2-3 workers, the potential stock market will reach 1800-2500 million units, taking into account a lot of jobs cannot substitute robots, may the actual market is not so big. We discussed with industry experts, five years can be seen in the domestic market sales reached 50-60 million units.Prediction of the sales of industrial robots in the global market AnalysisII.One of the development trends of industrial robots: more flexibleIn order to increase the use of industrial robots, the robot is more flexible. DFKI (German Research Center for artificial intelligence, is Germany's top intelligence research institutions, is currently the world's largest non-profit artificial intelligence research institutions, its shareholders include Google, Intel, Microsoft, BMW, SAP, Airbus, the global top ten enterprises of science and Technology) developed intelligent assembly robot, can through the abstract memory system for assembly, adaptive grasping and intelligent products specifically, is in the head mounted stereoscopic camera, camera mounted near the object in the arm; at the same time, using the left internal antenna reads from the inside of the product size, weight and hot.DFKI Grasping and assembling robotInter-generational evolution of industrial robots: robots are undergoing a shift from "machine" to human. We can divide the robot into three generations, the first generation of traditional industrial robots, which have not changed significantly for nearly 50 years. The second generation is a "feeling" robot. They have a certain sense of perception in the outside world, with visual, tactile and auditory functions. Such as a cooperative robot, a arc welding robot that automatically tracks the weld according to the laser feedback. The third generation planning based on artificial intelligence technology, robot control, according to their perception of information, independent thinking, recognition and reasoning, and make judgments and decisions, without human intervention automatically, become the main production system, can even replace machine and other machine tools, such as cloud service robot.The robot is undergoing a change from "machine" to "man"The second generation of robot representatives: UR cooperative robot. At present, cooperative robots occupy a part of the market with their safety, low cost, easy to use and low cost of transformation, especially for small and medium-sized enterprises which are mainly small batch and customized. However, in the long run, human-computer cooperation is the direction, and the potential of the cooperative robot market is great.UR5 apply in Volkswagen automobile production lineBecause of the great prospect of the cooperative robot, the robot enterprises both at home and abroad have the product development and sale, and have obtained the better market response. Although the domestic collaboration robot started late, but in the past two years, many products appeared in the development. In China, especially for the electronics industry, the domestic cooperative robot has a promising commercial prospect.Typical enterprise and product of cooperative robotThe third generation of robot - cloud service robot. Cloud service robots, integrating the latest information technology, will produce more dramatic changes in the impact of artificial intelligence and industrial robots.In 2015, the domestic industrial robot AIFUTE leading enterprises began the layout of the next generation of robot technology, and the Silicon Valley in the United States set up R & D center. A preliminary cloud robot platform product will be formed in 2018.The concept of cloud evert robotIII.The two development trend of industrial robots: low cost economy OntologyThe medium and small businesses can receive the longest payback period of two years, preferably one year, so the industrial robots should be popularized in China. In the long run, the price should be controlled at least 100 thousand. ConclusionIV.Prediction about Industrial RobotIndustrial robot in 10 years ago, the average selling price of about 500 thousand, the price is now four large family robot 15-20 million, Eft, and other domestic price slightly lower than the eston robot four family, economic type of pure domestic robot (terminal sales price of about 80 thousand. It is estimated that in the future, the average price of industrial robots will be reduced to less than 50 thousand with the localization of the spare parts and other parts.  Book Recommendation House of Robots: Robot Revolution Hardcover – January 16, 2017After a few early glitches in their relationship, Sammy and his "bro-bot" E are now fast friends. In fact, E is such a valued member of the family that the other electronic occupants of the House of Robots are feeling sorely unappreciated. And when Sammy's inventor mom becomes distracted by a top-secret project, the robots soon begin to fall into disrepair.Cue a robot revolt, with the droids wreaking harmless havoc in the house! Armed with pranks like glue in the shampoo bottles and flying toast missiles, the robots demand to be cared for. It's up to Sammy and his disabled sister Maddie to keep the peace until his mom reveals her secret project...and why it was worth the wait.--James Patterson  (Author),‎ Juliana Neufeld (Illustrator),‎ Chris Grabenstein (Contributor) Rise of the Robots: Technology and the Threat of a Jobless Future Paperback – July 12, 2016What are the jobs of the future? How many will there be? And who will have them? As technology continues to accelerate and machines begin taking care of themselves, fewer people will be necessary. Artificial intelligence is already well on its way to making "good jobs" obsolete: many paralegals, journalists, office workers, and even computer programmers are poised to be replaced by robots and smart software. As progress continues, blue and white collar jobs alike will evaporate, squeezing working- and middle-class families ever further. At the same time, households are under assault from exploding costs, especially from the two major industries-education and health care-that, so far, have not been transformed by information technology. The result could well be massive unemployment and inequality as well as the implosion of the consumer economy itself.The past solutions to technological disruption, especially more training and education, aren't going to work. We must decide, now, whether the future will see boad-based prosperity or catastrophic levels of inequality and economic insecurity. Rise of the Robots is essential reading to understand what accelerating technology means for our economic prospects-not to mention those of our children-as well as for society as a whole.--Martin Ford  (Author)Robot-Proof: Higher Education in the Age of Artificial Intelligence (MIT Press) Hardcover – August 25, 2017How to educate the next generation of college students to invent, to create, and to discover -- filling needs that even the most sophisticated robot cannot.Driverless cars are hitting the road, powered by artificial intelligence. Robots can climb stairs, open doors, win Jeopardy, analyze stocks, work in factories, find parking spaces, advise oncologists. In the past, automation was considered a threat to low-skilled labor. Now, many high-skilled functions, including interpreting medical images, doing legal research, and analyzing data, are within the skill sets of machines. How can higher education prepare students for their professional lives when professions themselves are disappearing? In Robot-Proof, Northeastern University president Joseph Aoun proposes a way to educate the next generation of college students to invent, to create, and to discover -- to fill needs in society that even the most sophisticated artificial intelligence agent cannot.A "robot-proof" education, Aoun argues, is not concerned solely with topping up students' minds with high-octane facts. Rather, it calibrates them with a creative mindset and the mental elasticity to invent, discover, or create something valuable to society -- a scientific proof, a hip-hop recording, a web comic, a cure for cancer. Aoun lays out the framework for a new discipline, humanics, which builds on our innate strengths and prepares students to compete in a labor market in which smart machines work alongside human professionals. The new literacies of Aoun's humanics are data literacy, technological literacy, and human literacy. Students will need data literacy to manage the flow of big data, and technological literacy to know how their machines work, but human literacy -- the humanities, communication, and design -- to function as a human being. Life-long learning opportunities will support their ability to adapt to change.The only certainty about the future is change. Higher education based on the new literacies of humanics can equip students for living and working through change.--Joseph E. Aoun (Author)  Relevant information about "The Future Market of Industrial Robots in China will Be Far Beyond Imagination"About the article "The Future Market of Industrial Robots in China will Be Far Beyond Imagination", If you have better ideas, don't hesitate to  write your thoughts in the following comment area. You also can find more articles about electronic semiconductor through Google search engine, or refer to the following related articles. Living Insect-Machine Hybrid Robot--Swarming Search and RescueMake Robots Walk NaturallyEngineers from MIT Developed A Tiny, Affordable Robotic Device That Can Detect Water LeakThree Fingers Robotic Hand with Specialized Sensors can Estimate Size and Shape of ObjectsA New, Electronic Skin Microsystem Enables People Tracks Their Heart Rate And Other Health Index

Warm hints: The word in this article is about 2500 and  reading time is about 12 minutes. Summary In the power system, in addition to the traditional harmonic sources, such as electric arc furnace and frequency converter, the nonlinear loads such as new energy access and charging pile may produce a lot of harmonics. In order to prevent harmonic from further affecting the power grid, accurate monitoring and timely treatment of harmonic level in power grid is a necessary step. The correct measurement of harmonic content in power grid is the basis of monitoring and governance. This paper mainly introduces some basic  knowledge about capacitor voltage transformer including the capacitor voltage transformer symbol; testing; working principle; capacitive voltage transformer VS inductive voltage transformer and etc. Article core capacitor voltage transformer Abbreviation CVT English name capacitor voltage transformer Category Power Subject Power engineer compose Capacitive voltage divider and medium voltage transformer Field Energy         Catalogs I. What is Capacitor Voltage Transformer( CVT)3.1 Insulation Resistance Measurement1.1 The Composition of CVT3.2 Capacitance Measurement1.2 CTV Judgment of Common Anomalies3.3 Pressure Swing Ratio Test1.3 CVT Equivalent Circuit Model3.4 Polar MeasurementII.Terminal Sign of Capacitive Voltage TransformerIV.Working Principle of Capacitive Voltage Transformer （CVT)III.Capacitor Voltage Transformer TestingV.Capacitive Voltage Transformer VS Inductive Voltage TransformerⅥ. FAQ  Introduction I. What is Capacitor Voltage Transformer( CVT) 1.1 The composition of CVT 一、The capacitive voltage transformer is mainly composed of a capacitor voltage divider and a medium voltage transformer. The capacitor divider is made up of porcelain bushing and series capacitors installed in it. The porcelain bushing is filled with insulating oil that keeps 0.1MPa positive pressure, and steel bellows are used to balance different environments to maintain oil pressure. The capacitor divider can be used as a coupling capacitor to connect the carrier device. The medium voltage transformer is composed of a transformer, a compensating reactor, a lightning arrester and a damping device installed in a sealed tank, and the space on the top of the tank is filled with nitrogen. The primary windings are divided into main windings and fine tuning windings, and a low loss reactor is connected in series between one side and one winding. Due to the capacitance and the inherent nonlinear impedance of the capacitor voltage transformer sometimes cause Ferroresonance in capacitor voltage transformer, thus suppressing resonant damping device, damping device is composed of a resistor and reactor, connected across the two windings, normally the damping device has very high impedance, when iron magnetic resonance caused by overvoltage in medium voltage transformer affected before the reactor is saturated only resistive load, the oscillation energy will soon be reduced. 1.2 CTV Judgment of common anomalies (1)The secondary voltage fluctuation. The two connection is loose, the distributor is not grounded or the carrier coil is not connected. If the damper is a fast saturable reactor, it may be improper parameter matching. (2)The Secondary voltage is low. Its connection is bad and the electromagnetic unit failure or the capacitor unit C2 is damaged. (3)The secondary voltage is high.The capacitance unit C1 is damaged and the ground end of the partial voltage capacitor is ungrounded. (4)The oil level of the electromagnetic unit is too high. The next capacitance unit is leaking oil or electromagnetic unit into the water. (5)There is a different sound in the transportation. Bolt loosening of reactor or medium pressure rheostat in electromagnetic unit. 1.3 CVT equivalent circuit model Under the condition of steady state, the whole CVT equivalent circuit can be regarded as a linear system, which compensates the stray capacitance of reactor C. The influence of the primary stray capacitance C: of the intermediate transformer at the high frequency can not be ignored. CVT intermediate transformer core can be regarded as linear segments in the magnetization curve, ignoring the core magnetizing inductance, one or two intermediate transformer side leakage resistance reduction to compensation reactor.   II.Terminal sign of capacitive voltage transformer · A single phase transformer with a two - time winding   It represents a single-phase transformer with two times winding. A represents the primary winding terminal of capacitive voltage transformer, and N represents the primary winding grounding terminal of voltage transformer. A represents the two winding terminal terminal of a capacitive voltage transformer, and N represents the first winding grounding terminal of the voltage transformer. · Single phase transformer with two two times windings   It represents a single-phase transformer with two two times windings, A represents the primary winding terminals of capacitive voltage transformers, and N represents the primary winding grounding terminals of voltage transformers. 1A and 2A represent the two winding terminals of the capacitive voltage transformer, and 1n and 2n represent the primary winding grounding terminals of the voltage transformer. · A single phase transformer with two two windings with a tap A single phase transformer with two taps and two winding is represented. A represents the primary winding terminal of capacitive voltage transformer, and N represents the primary winding grounding terminal of voltage transformer. 1A1, 1A2, 2a and 2A2 respectively represent the two winding terminals of the capacitive voltage transformer, and 1n and 2n represent the primary winding grounding terminals of the voltage transformer. · A single phase transformer with a residual voltage winding and two two times windings   It represents a single-phase transformer with a residual voltage winding and two two winding. The A represents the primary winding terminal of capacitive voltage transformer, and N represents the primary winding grounding terminal of voltage transformer. 1A1, 1A2, 2a and 2A2 respectively represent the two winding terminals of the capacitive voltage transformer, and 1n and 2n represent the primary winding grounding terminals of the voltage transformer. Da and DN represent the residual voltage terminal.   Detail III. Capacitor Voltage Transformer Testing 3.1 Insulation resistance measurement The insulation resistance should be measured by the main capacitor, the partial voltage capacitor and the one or two winding insulation resistance of the intermediate transformer. 3.2 Capacitance Measurement The purpose of the test is to determine whether the capacitance of the voltage divider has a change, and the capacitor is insulated without water and dampness.   3.3 Pressure swing ratio test The test transformer exerts high voltage as far as possible. Due to the rise effect in the test, the high voltage voltage must be measured at the high voltage end. The voltage transformer used must be level 0.1 or above to ensure the accuracy of the test results. After the voltage is applied at the high voltage side, the voltage of the low voltage side is measured in turn on the two side and in the auxiliary side, and the voltage ratio is compared with the pressure ratio of the nameplate. 3.4 Polar measurement The purpose of polar measurement is to check the mark of the nameplate. Test method: using DC method, CAR instantaneous addition of 1.5V battery power "+", "-" with "N", respectively, with a multimeter or mA DC or mV meter, pay attention to the polarity put right, A1, A0 "+" X1, XD "-" pointer in the power supply to the deflection of the "+" direction; open to "-" deflection. The test of polarity and pressure variable ratio of windings is usually done in hand over and after overhaul.   IV. Working Principle of Capacitive Voltage Transformer （CVT) There is a video about CVT:   This vidoe explained How Capacitor Voltage Transformer CVT works.Capacitor potential transformer concept is explained.What is high voltage measurement using capacitor type voltage transformer is explained. How to measure high voltage? Educational tutorial on electrical engineering 126 by G K Agrawal. The basic part of the capacitive voltage transformer is the capacitor voltage divider, and it also includes the electromagnetic parts such as the intermediate transformer, the compensating reactor, the damper and so on. Its principle connection is shown in the following picture,the picture shows capacitor voltage transformer wiring diagram capacitance divider is composed of main capacitor C1 and voltage divider capacitor C2 series. Without considering the electromagnetic part, the voltage is divided by capacitance. The voltage on C2 is the following formula: K is the partial voltage ratio. When the two ends of the C2 are connected to the two load, due to C1, C2 The basic part of the capacitive voltage transformer is the capacitor voltage divider, and it also includes the electromagnetic parts such as the intermediate transformer, the compensating reactor, the damper and so on. Its principle connection is given below.   The capacitor voltage divider is composed of the main capacitor C1 and the partial voltage capacitor C2 in series, without considering the electromagnetic part, then the voltage is divided according to the capacitance inverse ratio, and the voltage on the C2 is:   In this formula,K is the ratio of partial pressure When the two ends of C2 are connected to two loads, the larger capacitance internal impedance is due to the existence of C1 and C2, which makes UC2 smaller than the capacitance partial voltage. The larger the load current is, the greater the error is. In order to reduce the capacitance internal impedance, a compensatory reactor L can be connected in series, and the UC2 is not related to the load as much as possible. In fact, because the capacitor has loss, the reactor also has resistance, so that the internal impedance can not be zero, so when the load changes, there will always be error. In order to further reduce the effect of load current, the measuring instrument is connected to the divider after the intermediate transformer TV is boosted. When the two side transformer short circuit occurs, the resistance in the circuit and the total reactance reactor L after compensation are very small, several times the short-circuit current may reach the rated current, will produce a very high voltage resonance in L and C2, in order to prevent overvoltage caused by the breakdown of insulation in capacitor C2 parallel at both ends of the discharge gap F1. Capacitor voltage transformer with capacitance and nonlinear inductance (e.g. TV magnetizing inductance etc.), when the transformer side suddenly close or receive two side and eliminate the impact of sudden short circuit, overvoltage in the transient process may cause nonlinear inductor saturation, which excite ferroresonance overvoltage, such as harmonic 1/3 resonant.  Because the resistance is very small, the resonance will last for a long time, which will cause damage to voltage transformers, instruments and relays, and may lead to incorrect operation of the protective devices. Therefore, the damping resistance RD or damper is often installed on the two side of the capacitive voltage transformer to consume the resonant energy as soon as possible to suppress the ferroresonance. For a common capacitive voltage transformer, a resonant damper is used. It is the capacitance and the inductor in parallel and then added to the damping resistance. In UHV power grid, a capacitive voltage transformer often uses a fast saturation type damper, which is composed of a fast saturation reactance and a damping resistor.     Analysis V. Capacitive Voltage Transformer vs Inductive Voltage Transformer Inductive Voltage Transformers (IVT), are used for voltage metering and protection in high voltage network systems. They transform the high voltage into low voltage adequate to be processed in measuring and protection instruments secondary equipment, such as relays and recorders). A Voltage Transformer (VT) isolates the measuring instruments from the high voltage of the monitored circuit. VTs are commonly used for metering and protection in the electrical power industry. It’s a standard transformer available in the market for step-up or step-down voltages. The advantage is it can be used for high load current and provides isolation.   However,as we mentioned in the above,capacitor voltage transformer is a specialized circuit whose purpose is to convert a high voltage AC signal to lower voltage, usually used with very high input voltages, and a large ratio between input and output voltage. It's usually only used in cases where you're trying to extract a very small amount of power from a high-power circuit, usually for monitoring the high-power circuit. Its advatage is economical but there is no galvanic isolation.   Ⅵ. FAQ 1. What is the function of capacitor voltage transformer?A capacitor voltage transformer (CVT), also known as capacitor-coupled voltage transformer (CCVT), is a transformer used in power systems to step down extra high voltage signals and provide a low voltage signal, for metering or operating a protective relay.   2. Why is CVT used?One of the advantages of a CVT is its ability to continuously change its gear ratio. This means that no matter what the engine speed it, it is always performing at its peak efficiency. CVTs often offer better fuel economy as a result, especially when driving in the city. ... This is because the transmission never shifts.   3. What do you understand CVT and CCVT?Capacitor Voltage Transformer (CVT) or Capacitor Coupled Voltage Transformer (CCVT) is a switchgear device used to convert high transmission class voltage into easily measurable values, which are used for metering, protection, and control of high voltage systems.   4. Why are capacitors used in transformers?At too high common mode frequencies, the inevitable capacitive coupling in the transformer will cause some of the common mode signal on the input to show up as signal on the output. The capacitor provides a more serious connection to ground for AC, while the resistor only a weak connection for DC to avoid ground loops.   5. Why is CVT hated?Because CVTs tend to lock an engine into a specific RPM, generally a high and noisy RPM, making the whole experience very hard on the ears. Also, CVTs are generally tuned for fuel economy rather than performance, and most of the magazines out there are wannabe racecar drivers.   6. What is the function of capacitor voltage transformer?A capacitor voltage transformer (CVT), also known as capacitor-coupled voltage transformer (CCVT), is a transformer used in power systems to step down extra high voltage signals and provide a low voltage signal, for metering or operating a protective relay.